2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/73384We transfer a large part of the circle of theorems characterizing the generalization of classical $H^\infty$ known as `weak* Dirichlet algebras', to Arveson's noncommutative setting of subalgebras of finite von Neumann algebras.18 pages: Minor technical improvements to Szego's theoremOperator AlgebrasFunctional Analysistext